In the comics, the Dark Phoenix storyline spans nine issues from X-Men #129 to #138 as well as multiple issues prior with Jean Grey as the Phoenix and her long history with the X-Men. 'The Dark Phoenix Saga' is one of, if not the most famous X-Men storyline around and two attempts to adapt it into film have been made to negative responses. Combining these two different storylines and merging them into one showed the franchise's willingness to draw from the source material while also forging its own path. The biggest was turning William Stryker from the leader of a religious fanatic to a military scientist, particularly the one responsible for giving Wolverine his adamantium claws, merging the storyline with the famous Weapon X story from the comics. While the key plot points of the X-Men and Magneto teaming up, and Stryker using Xavier to try and kill all the worlds' mutants remained the same, the film did make some changes. Related: Every X-Men Movie Ranked by Box Office Gross Published in 1982 by writer Chris Claremont and artist Brent Anderson, the storyline saw Magneto team up with the X-Men to save Charles Xavier from Reverand William Stryker from using Xavier's telepathic powers to kill all mutants.

X2: X-Men Unitedon the other hand drew inspiration from a particular storyline titled X-Men: God Loves, Man Kills. The first X-Men is very much its own unique story but is the classic X-Men vs the Brotherhood of Mutants story that was seen across the franchise.

X-Men by Brent Anderson